1. Field of the Invention
The present invention relates to a semiconductor device packaged into a chip size and a manufacturing method thereof.
2. Description of the Related Art
The present invention is an improvement to the type of semiconductor devices having a conventional chip size and a configuration in which a semiconductor substrate has a lower surface carrying an integrated circuit and a plurality of connection pads connected with the integrated circuit, and being covered with a first sealing film. The upper surface and peripheral side surfaces of the semiconductor substrates are covered with a second sealing film. A wiring is provided on an upper surface of the second sealing film to be electrically connected with the connection pads, a columnar electrode is provided on each connection pad portion of the wiring and a periphery of the columnar electrode is covered with a third sealing film in order to increase a protection effect for an environment, e.g., dust, humidity, a mechanical damage and others as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2001-332643. In this case, the first to third sealing films are formed of an organic material such as an epoxy-based resin or a polyimide-based resin.
In the conventional semiconductor device, the wiring is provided on the upper surface of the second sealing film which covers the upper surface and the peripheral side surfaces of the semiconductor substrate, and the third sealing film covers the periphery of the columnar electrode provided on each connection pad portion of the wiring. Therefore, the wiring comes into contact with the second and third sealing films, and the columnar electrode is brought into contact with the third sealing film. Since an organic material such as an epoxy-based resin or a polyimide-based resin which is a material of the second and third sealing films contains impurities such as an Na ion, a K ion, a Ca ion and Cl ion, a high concentration of the impurities can be a factor which provokes corrosion of the wiring or the columnar electrode or short circuit between these members. In order to avoid such an inconvenience, each impurity concentration of the Na ion, the K ion, Ca ion and the Cl ion in an organic material such as an epoxy-based resin or a polyimide-based resin which is a material of the second and third sealing films must be greatly decreased to 10 ppm or lower, thereby increasing a sealing material cost.